The “Prince of Persia” is a dashing rogue with sculpted muscles and a backbone of steel who teams with a lovely princess to protect an artifact that could determine the fate of all mankind. Fearless and mighty, he is an adventure hero of the highest order.

He is played by Jake Gyllenhaal.

Wait a sec. Jake Gyllenhaal?

Well, non-believers, before you scoff, there was a similar reaction when Matt Damon was tabbed to play government assassin Jason Bourne, and that seemed to work out OK. Gyllenhaal, 29, has already sampled a wide variety of delicacies from the acting buffet so far in his career, including indie turns in “Donnie Darko” and “Lovely & Amazing,” choice roles in prestige releases such as “Brokeback Mountain” and “Brothers,” and even a major part in the Roland Emmerich disaster flick, “The Day After Tomorrow.”

Such an eclectic palate is admirable, but one curious by-product is that it prevents the Hollywood establishment and movie audiences from getting a handle on who Jake Gyllenhaal is, at least as a bankable actor. Is he an independent character actor? A leading man? An action figure? A love interest or a second banana? Is he rough and tough, or vulnerable and sensitive?

Can someone like Gyllenhaal have a long career even though he may defy categorization in a town where even its pigeons are pigeonholed?

“Gyllenhaal’s a real 21st century leading man — the guy who doesn’t play it safe,” said Mary Elizabeth Williams, film critic and contributor to Salon.com and other publications, as well as the author of “Gimme Shelter,” an amusing look at the home-buying process.

“In a lot of ways,” she added, “he’s like Brad Pitt, Robert Downey Jr., or to name one of his peers, Christian Bale. They’re all charismatic, handsome stars, and they can carry a big action movie whenever they want to — but they know the key to longevity is to keep challenging audience expectations of them. To look at the guy, he’s made to be on movie posters.”

Muscled look on poster causes double takesAh, yes, the poster. The one-sheet for “Prince of Persia: The Sands of Time,” which opens Friday, depicts Gyllenhaal in full warrior pose, looking as chiseled as the employee of the month at Gold’s Gym. Even director Nicole Holofcener, who cast Gyllenhaal in her 2001 film “Lovely & Amazing” fresh off his breakthrough in “Donnie Darko,” said she did a double take.

“I said, ‘Who’s that?! Jake?!’ But he probably sees that poster and thinks the same thing,” Holofcener said. “But who can blame him for taking that part? He probably had a blast doing it.”

She said she chose Gyllenhaal for the part of Jordan in “Lovely” because “he had innocence and sexiness, a great sense of humor and an earnestness. And he was just so damn cute. That’s what it boiled down to. Everybody in the room during casting was blushing, so I figured that was a good sign.

“I’m thrilled for his career. I’m not surprised at all at where he’s at. When I cast him there was this feeling that he was going to be really big.”

Certainly, Nicolas Cage is really big, too. But after Cage won an Academy Award for “Leaving Las Vegas” in 1996, he became known less for art than commerce, starring in such big-payday pictures as “The Rock,” “Con Air,” “National Treasure” and “Ghost Rider.”

To be fair, Cage over the years has also mixed in more cerebral work in films like “Adaptation” and “Matchstick Men,” yet his penchant for starring in blockbusters became so magnified that it caused Sean Penn — who appeared with Cage in “Racing With the Moon” and, to a much lesser extent, “Fast Times at Ridgemont High” — to once famously remark to The New York Times, “Nic Cage is no longer an actor. He could be again, but now he’s more like a … performer.”

Could Gyllenhaal’s career lose traction from too much action?

“His next project is from ‘I Heart Huckabees’ director David O. Russell (“Nailed,” co-starring Jessica Biel), so it seems clear he wants to keep stretching,” Williams said. “What Gyllenhaal brings to fare like ‘Prince of Persia’ is his light, funny touch. He’s not just sword-wielding beefcake, nor does he appear to want to be. There’s nothing wrong with a little popcorn in any career, but he’s not making a steady diet of it.

“And he’s one of the few stars, like Matt Damon, who can do action, drama, comedy and weirdo indie. I don’t think it’s just about getting the fattest paycheck — it’s about doing what he hasn’t done before.”

Options are endless, plus he's a gentlemanDavid Kagen is one of the top acting teachers in Hollywood. He said Gyllenhaal possesses rare qualities for an actor, and as a result his career options are many.

“There are a lot of actors I’ve worked with where you talk to them and they open up and this wonderful personality comes out,” Kagen said. “All this stuff that’s particular to them that’s interesting. Then you hand them a script and a lot of that goes away. And that’s really bad. One of the things they need to learn is to use themselves, and then get out of the way.

“When I see Jake doing interviews, and then watch him in something like ‘Brothers,’ there’s no change. It’s like this wonderful seamless transition into whatever role he’s playing. Everything seems to be available to him, his sense of humor, his toughness. There is a sort of an ease. … There are just some people who have that.”

That was also apparent to cinematographer Steven Poster, who shot “Donnie Darko” in 2001, featuring a 20-year-old Gyllenhaal. “There was such intelligence with his characterization of Donnie,” Poster said. “You knew from the beginning he would be big. Plus, he was a gentleman. There wasn’t a moment of ego or narcissism.”

Poster believes the actor’s presence in “Prince of Persia” represents an opportunity for Gyllenhaal to have some fun rather than signal a dubious step down an unfortunate career path. “I think Jake is very smart that way,” he said. “Everybody’s got to do one of these pictures on the way up. … I think he’s very grounded.”

In Hollywood, there is often a chasm between how an actor views himself and what the business sees him as. Holofcener, for one, hopes Gyllenhaal doesn’t spend much time thinking about any of that.

“Hopefully he’s not trying to figure out who he is,” she said. “I hope he just keeps taking roles that appeal to him.”

Michael Ventre is a frequent contributor to msnbc.com. He lives in Los Angeles.